The highest day temperature in January 2026 was 53°F. The lowest night temperature was 26°F. The average values for day and night temperatures during January were 46.5°F и 38.2°F respectivly.

You can expect various weather conditions during January. Be ready for sunny, cloudy or even gloomy days.

Precipitation total in January for Siena is 1.6 in. It makes january one of the least rainy months of the year.

The average wind speed in January is 5.5 mph. This value is relatively stable throughout the year.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Siena in January is 5.1 hours.